Southern California Edison said power was cut to more than 75,000 customers in Los Angeles, Orange, Riverside, Ventura and San Bernardino counties as of Thursday evening. Shutoffs were possible for another 140,000 customers in seven counties.
The utility cuts the power during strong Santa Ana-wind events because of the risk from power lines and equipment being damaged and sparking wildfires.
Edison says power is usually restored from three to eight hours after the dangerous conditions have subsided, meaning most likely not until sometime Friday.
Red flag warnings went into effect Wednesday morning and will remain in effect through much of Friday due to strong gusts and low relative humidity, the National Weather Service said.
The extreme gusty conditions knocked over a massive tree in North Hollywood overnight, sending it crashing through the roof of a home, which has been red-tagged. Residents in the area were startled by the boom sounding off as the tree snapped.
The man who lives at the home said he suffered a bruise to his leg when it smacked down, but is fine otherwise.
Some Orange County neighborhoods also saw damage from the strong winds. Surveillance video captured the moment a large tree on the 300 block of South Pacific Avenue in Santa Ana fell over onto parked cars.
Two other trees were reported down on the 2200 block of South Magnolia as well as the 2100 block of West Chestnut near Lincoln Elementary School.
In Westminster overnight, the strong wind may have sparked several fires when it pulled down some power lines, knocking a tree over.
A shed caught on fire and the flames spread to other homes nearby. Fire crews called it a challenging night trying to secure downed power lines while contending with strong gusts.
The Associated Press contributed to this report.